Generally, soft capsules comprising an oil-insoluble or powder active ingredient are produced by preparing a dispersion of the active ingredient in an edible oil and filling the dispersion in capsules each having a gelatin coating. In the production, as a dispersant for distributing the active ingredient stably in the edible oil, a glycerol fatty acid ester and bees wax have been conventionally used (see Patent Literature 1).
However, soft capsules in which bees wax is used as the dispersant are known to have a problem; the active ingredient, which can sufficiently disperse in an edible oil, only poorly disperses in vivo after taken into the body, resulting in insufficient effect of the active ingredient. Means for solving the problem, such as a composition in which the active ingredient is suspended by a combination of, for example, a glycerol fatty acid ester and a hydrogenated oil, have been proposed (see Patent Literature 2).
However, the above-mentioned technologies are not necessarily satisfactory from a practical standpoint.